Can corydoras live with cardinal tetras?

Verdict
Yes

Yes. Corydoras and cardinal tetras get along in the same tank. Both are fine at 76–79°F. Plan on at least 20 gal.

CorydorasCorydoras72–79°F · pH 6–7.8 Cardinal tetraCardinal tetra76–84°F · pH 4.6–7

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–79°Corydoras 72–79°Cardinal tetra 76–84°
The green band is the temperature range both can live in.
456789Both: 6–7Corydoras 6–7.8Cardinal tetra 4.6–7
The green band is the pH both tolerate.

Size to scale

Corydoras · 2.5 inCardinal tetra · 2 in0"1"2"3"4"5"6"
Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

CorydorasCardinal tetra
Temperature72–79 °F76–84 °F
pH6–7.84.6–7
Adult size2.5 in2.0 in
Minimum tank20 gal20 gal
TemperamentPeacefulPeaceful
Swims atBottomMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for corydoras

All corydoras tank mates

Better tank mates for cardinal tetras

All cardinal tetra tank mates

Questions

Can corydoras live with cardinal tetras?

Yes. Corydoras and cardinal tetras get along in the same tank. Both are fine at 76–79°F. Plan on at least 20 gal.

What temperature suits both corydoras and cardinal tetras?

76–79 °F. Corydoras need 72–79 °F, cardinal tetras need 76–84 °F.

What size tank do corydoras and cardinal tetras need together?

At least 20 gal, set by the corydoras. Add space for each extra fish.